When is it okay for girls to play on boys' sports teams?

This question is really easy to answer because it should have been okay for girls to play on Boy's sports teams years ago. Unless, the girls had their own same sport team already; it wouldn't be fair for the girls to join the boys team when their had their own. It wouldn't be fair if the boys had a sports team that the girls didn't have because the girls might feel that the boys are cared more. I think from the publicity point of view, it might look weird if a boy joined a girl sports team than a girl joining a boys sports team because a girl can do what a boy does but, it will look weird for a boy to do what a girl does. From my point of view, it doesn't make a difference if a girl joined a boys sports team or a boy joined a girls sports team because the sport that the two genders are playing is equally same , except for the rules maybe.

When is it okay for boys to play on girls' sports teams?

Like I said on the first question, it doesn't make a difference if a boy/boys played on a girls team or a girl/girl played on boys team. So my answer is years ago! But I don't think there isn't that much boys going on a girls team than girls going on boys team because like the olden times ages ago, boys were treated more highly than the girls. The people thought that girls shouldn't have much equality as the boys.